Cell Membranes, Movement across Membranes and DNA Structure

Question 1

Hydrophilic

Answer 1

attracted to water

Question 2

Hydrophobic

Answer 2

repels water

Question 3

Polar

Answer 3

charged due to the unequal sharing of electrons

Question 4

What do phospholipids consist of?

Answer 4

• a phosphate group (forms phosphate head)
• a molecule of glycerol
• two fatty acids (forms lipid tail)

Question 5

properties of phospholipid head

Answer 5

• polar and can therefore interact with polar water molecules
• hydrophilic

Question 6

properties of phospholipid tail

Answer 6

• non-polar, cannot interact with polar water molecules
• hydrophobic

Question 7

proteins function

Answer 7

involved with cell transport and communication

• integral proteins are embedded in the membrane with their precise arrangement determined by their hydrophilic and hydrophobic regions
• peripheral proteins are found on the outer or inner surface of the membrane

Question 8

cholesterol function

Answer 8

regulates membrane fluidity

• can be found between phospholipids
• increases fluidity of the membrane at low temperatures, stopping it from becoming too rigid
• decreases fluidity at high temperatures to stabilise cell membrane
• increases mechanical strength of membranes

Question 9

glycolipids and glycoproteins function

Answer 9

lipids and proteins with polysaccharide (carb) chain attached
aid cell-to-cell communication

• present on the surface of the cell
• bind with substances at the cell’s surface

Question 10

bulk transport

Answer 10

a cellular process by which large amounts of material are transported in or out of the cell in membrane-bound sacs called cysts

Question 11

what is DNA?

Answer 11

deoxyribonucleic acid

double-stranded helical polynucleotide containing the genetic code of an organism

Question 12

How are mononucleotides linked together?

Answer 12

a condensation reaction between the sugar of one nucleotide & phosphate of next forms a phosphodiester bond and produces a polynucleotide

Question 13

nucleic acid

Answer 13

long polymer chains created by the joining of nucleotide monomers

Question 14

monomers of nucleic acids

Answer 14

adenine, thymine, cytosine, guanine

Question 15

DNA molecule structure formation

Answer 15

two antiparallel complementary polynucleotide strands join by hydrogen bonding between complementary base pairs, forming the DNA double helix